The New Zealand wrens (Acanthisittidae) consist of seven recent and one Miocene fossil species placed in six genera. Acanthisittidae was the earliest family of songbirds to separate from the rest of the Order, and so they are the sister group to all other songbirds. Only the rifleman and rock wren are extant. The long-billed wren was the rarest of the recent acanthisittids and is known from the remains of possibly 6 individuals from 4 cave sites in northwest Nelson and Southland. The holotype (NMNZ S27775, partial skeleton) and paratype (NMNZ S22940, a mandible) are held at the Museum of New Zealand, Te Papa. The type locality of the species is the Moonsilver Cave, northwest Nelson and the paratype was collected from the Honeycomb Hill Cave, Buller District.

This flightless wren weighed about 30 g, approximately twice the weight of the rock wren which is the heaviest extant acanthisittid. The long-billed wren had a large head, small wings, and short, relatively weak legs. Its most distinguishing feature was a long, down-curved bill from which its specific name is derived. The etymology of its generic name comes from the Greek dendros (a tree) and Latin scando, scansus (climb) referring to its supposed arboreal, trunk-foraging habit. However, it now appears that the bird lived mainly in subalpine scrub and tussock and was absent from the lowland forest of eastern South Island. Like other New Zealand wrens it was probably an insectivore.

The long-billed wren is known from late Pleistocene and Holocene deposits and probably became extinct shortly after human settlement. Its flightlessness and probable ground-nesting habits would have made it easy prey for the Pacific rat.

References

Millener, P. R.; Worthy, T. H. 1991. Contributions to New Zealand’s Late Quaternary avifauna. II: Dendroscansor decurvirostris, a new genus and species of wren (Aves: Acanthisittidae). Journal of the Royal Society of New Zealand 21: 179-200.